David Attenborough chronicles the forensic investigation of an amazing find in the Argentinean desert: the fossils of a giant-sized, plant-eating titanosaur. The discovery was due to a shepherd who, while searching for one of his lost sheep, spotted the tip of a gigantic bone sticking out of a rock. The fossils, which date to 101.6 million years ago, point to the creature being the largest dinosaur thus far known. It measured 121 feet from head to tail and weighed over 77 tons.

Reunions between wild animals and their caregivers reveal whether interspecies bonds can stand the test of time.